/**
 *
 * @param ms
 * @return {Promise<any>}
 */
exports.sleep = (ms) => {
  return new Promise(resolve => setTimeout(resolve, ms));
};


/**
 *
 * @param date
 * @return {string}
 */
exports.dateToString = (date = new Date()) => {
  return date.getFullYear() + '_' + date.getMonth() + '_' +
      date.getDate();
};